leadTerm(n,I)
i1 : R = QQ[a..d,MonomialOrder=>ProductOrder{1,3}];
i2 : I = ideal(a*b-c*d, a*c-b*d) o2 = ideal (a*b - c*d, a*c - b*d) o2 : Ideal of R
i3 : leadTerm(1,I) o3 = | b2d-c2d ac ab | 1 3 o3 : Matrix R <-- R